While I don't discount that IDEO started from scratch and became a powerhouse using the methodologies described in the book, I would assert that their techniques and suggestions are only valuable to design firms, consultants, and high-end designers within very large corporations.
Some of the ideas are neat and can be incorporated into other structures - particularly the advice on brainstorming. But much of the work is simply not feasible for the average project or department manager. I do understand the inefficiencies that come from poorly executed innovation, prototyping, etc., but as far as functional guidelines go, a basic Product Design textbook has more useful and more flexible process descriptions.
Nevertheless, the book is at least entertaining, and is probably another route to making loads of dough for the IDEO guys, which, after all, is what IDEO seems to do best!
